Just a quick update on SCELBI progress…

I have completed schematic layout comparisons of three of the five main 8H boards. What this means, is that I have compared the layout to the schematics and corrected any unexplainable differences between the two. This is a time consuming process, but I did find a few mistakes in my layout, so this has been worthwhile. I also found (for the second time) that there is one small mistake in the DBB board schematic. I also discovered that there were two versions of the DBB board made (I am laying out the later version) The boards I have completed this check on, are the front panel board, the CPU board and the DBB board. The CPU and DBB boards are fairly complex and took a while to do.

The remaining boards, input and 1K memory, are less complex and shouldn’t take quite so long. After these two boards are checked, I have to do some checking of pads and hole dimensions for discrete components. I learned some time ago that getting hole sizes right is as critical as any other single part of this process. After the dimension checks are complete, I have a final CAD check left to do, before getting quotes and the boards sent off to be made.

I also have done some work on the 8H backplane. The backplane is starting to shape up, but I’m not sure if I will have these built along with the five main cards or not, since with a SCELBI you can hardwire a backplane.